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A185179 Irregular triangle, read by rows, of the A185178(n) values of the permanent of an n X n (0,1)-matrix (n>=3) with exactly three 1's in each row and each column.

%I A185179 #36 Jul 27 2025 11:15:43
%S A185179 6,9,12,13,17,18,20,36,24,25,26,27,30,31,32,54,33,34,35,36,37,38,39,
%T A185179 40,41,42,44,45,48,49,52,72,78,81,42,44,45,46,47,48,49,50,51,52,53,54,
%U A185179 55,56,57,58,59,60,62,63,64,66,68,70,72,78,84,102,108,117,120,216
%N A185179 Irregular triangle, read by rows, of the A185178(n) values of the permanent of an n X n (0,1)-matrix (n>=3) with exactly three 1's in each row and each column.
%D A185179 V. I. Bolshakov, On spectrum of permanent on Lambda_n^k, Proc. of Seminar on Discrete Math. and Appl., Moscow State Univ. (1986), 65-73 (in Russian).
%H A185179 Robert P. P. McKone, <a href="/A185179/a185179_1.txt">Complete and Known Values of the Permanents A185178(9-15)</a>
%H A185179 V. S. Shevelev, <a href="http://dx.doi.org/10.1007/BF01104103">Some problems of the theory of enumerating the permutations with restricted position</a>, Journal of Soviet Mathematics, 61 (4) (1992) 2272-2317 (see pp. 2307-2309).
%e A185179 Triangle begins:
%e A185179   6
%e A185179   9
%e A185179   12, 13
%e A185179   17, 18, 20, 36
%e A185179   24, 25, 26, 27, 30, 31, 32, 54
%e A185179   33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 48, 49, 52, 72, 78, 81
%e A185179   42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 62, 63, 64, 66, 68, 70, 72, 78, 84, 102, 108, 117, 120, 216
%Y A185179 Cf. A185178, A185177, A176211, A176212.
%K A185179 nonn,tabf,hard
%O A185179 3,1
%A A185179 _Vladimir Shevelev_, Feb 19 2011
%E A185179 More terms from _Robert P. P. McKone_, Jul 26 2025